<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>计算</title>
</head>
<body>
    <form method="POST" action="/cal/"> <!--action="/cal/"，cal必须以'/'结尾-->
        {% csrf_token %}
        <input type="number" name="valueA">
        +
        <input type="number" name="valueB">
        <input type="submit" name="提交计算">
    </form>
</body>
</html>